Optical waveguides – With optical coupler – Plural
Reexamination Certificate
1999-10-28
2003-08-05
Cherry, Euncha (Department: 2872)
Optical waveguides
With optical coupler
Plural
C385S037000, C359S199200
Reexamination Certificate
active
06603898
ABSTRACT:
FIELD OF THE INVENTION
The invention relates generally to optical filters and, more particularly, to minimizing loss and ripple in such filters.
BACKGROUND OF THE INVENTION
Many systems, such as wavelength division multiplexing (WDM), require filters with a relatively flat and smooth-topped spectral response. The prior art has shown that one can construct a filter with a flat spectral response by cascading two waveguide grating routers (WGRs) [1] (Note in this specification, a reference to another document is designated by a number in brackets to identify its location in a list of references found in the Appendix) I focus here on filters that consist of two cascaded gratings, such as waveguide gratings, connected by two or more connecting optical elements, such as waveguides, (which we will sometimes refer to as “back-to-back gratings”), such as shown in FIG.
1
. Examples of such filters include wavelength cross connects [2] wavelength equalizers [3], and wavelength add/drops [8].
Such back-to-back gratings do not generally exhibit a flat spectral response, and thus there is a need for providing design criteria for minimizing the loss and ripple in the spectral response through such back-to-back gratings.
SUMMARY OF THE INVENTION
In accordance with the present invention, I describe a design technique for minimizing the loss and ripple in the spectral response of an optical filter including one or more gratings, such as waveguide gratings, connected to an array of optical elements. I achieve the smoothest spectral response for a given set of connecting optical elements substantially periodically spaced by a distance “a”, by choosing the aperture size of the grating to be substantially equal to (f&lgr;)/a, where &lgr; is the wavelength of interest and f is the focal length of the grating.
REFERENCES:
patent: 6023480 (2000-02-01), Dragone
LandOfFree
Apparatus and method for achieving a smooth spectral... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus and method for achieving a smooth spectral..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and method for achieving a smooth spectral... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3118555